Currently, small-interval Light-Emitting Diode (LED) televisions are widely applied to various fields of public information display such as an information announcement of a hotel lobby, an airport, a cinema and a hospital, and indoor places such as corporate image publicity, exhibition of cultural relics of a museum, a meeting room, a club, a shopping mall and a hall. New-generation small-interval LED televisions have started to develop to home application.
A display circuit of a current LED television is composed of an LED lamp bead array, a column-oriented drive switch array, a row-oriented drive switch array and a discharge circuit. The LED lamp bead array is in charge of image display. The column-oriented drive switch array mainly comprises a constant current Integrated Circuit (IC), and is in charge of cathode pin control over common-anode LED lamp beads. The row-oriented drive switch array mainly comprises a Metal Oxide Semiconductor (MOS) array, and is in charge of control over an anode of a common-anode LED lamp bead array. The discharge circuit is mainly formed by connecting a resistor to a voltage-regulator diode in series, and is in charge of discharging excess electricity.
The LED lamp bead array is frequently opened and closed, excess electricity exists on a line within a closed time period, and the excess electricity will enable the LED lamp beads to be lighted in an LED turn-off process, so it is necessary to use the discharge circuit to discharge the electricity. FIG. 1 is a diagram of a discharge circuit in the traditional art.
The inventor finds that the existing discharge circuit has, at least, the problems as follows.
Under normal circumstances, an LED forms a path only for the ground via a constant current source. According to an existing discharge mode, after the LED is short-circuited, lamp beads in other columns will form a discharge path for the ground via the short-circuited LED by means of a voltage-regulator diode and a resistor in a turn-on process, current passing through the turned-on LED lamp beads is higher than current under normal circumstances, and the brightness of the lamp beads in this column is increased, thereby causing abnormal display of an LED television, namely a general short-circuit caterpillar phenomenon.
An effective solution is not proposed yet currently for the above problems.